CHEESE-RIPENING STUDIES: THE INFLUENCE OF THE CONFIGURATIONAL RELATIONS OF THE HEXOSES ON THE SUGAR-FERMENTING ABILITIES OF LACTIC ACID STREPTOCOCCI: A Preliminary Note

Abstract

The influence of the configurational relations of the hexoses on the ability of a Streptococcus cremoris strain to produce acid from lactose in milk and in broth has been studied.With casein digest broth as the nitrogen source, the organism was carried by serial transfers in 10 different carbon sources; at every transfer the cultures were inoculated from the sugar broths into milk, and the clotting times of the respective milk tubes determined.The carrying of the culture in sucrose, maltose, dextrin or starch has no influence on the acid-producing ability of the organism.Glucose, mannose, fructose, and salicin exhibit a marked inhibiting effect on the rate and amount of acid production in milk and in lactose broth.Although galactose and lactose fail to inhibit completely the activity of the organism, a restraining influence on acid production is to be observed. It is suggested that the inhibitory activity of glucose or one of its metabolic products may be a cause of the sudden or gradual loss of vitality in starters.